One hybrid vehicle configuration includes an engine that is directly coupled to a driveline disconnect clutch, and the disconnect clutch is directly coupled to a driveline integrated starter/generator (DISG), which is directly coupled to a torque converter impeller. The driveline may also include a dual mass flywheel that includes springs that operate with the flywheel's masses to provide mechanical dampening between the engine and the driveline disconnect clutch. The dual mass flywheel reduces amplitude of engine torque pulses that may be transferred to the vehicle's transmission and wheels. However, the flywheel's mass increases driveline inertia to decrease fuel economy. Additionally, the flywheel's inertia contributes to an increased inertia torque produced at an input shaft of a transmission. The increased inertia torque may increase driveline torque disturbances during transmission gear shifting because of an increased amount of torque being transmitted through transmission gear clutches increases. Therefore, it would be desirable provide the benefits of a dual mass flywheel while providing reduced inertia torque to a transmission input shaft during transmission gear shifting.
The inventors herein have recognized the above-mentioned disadvantages and have developed a method, comprising: proportionately adjusting a torque capacity of a torque converter clutch in response to an amplitude of an inertia torque produced via an inertia located upstream of the torque converter clutch, the inertia including inertia of a disconnect clutch and inertia of a motor, the disconnect clutch directly coupled to the motor.
By adjusting a torque capacity of a torque converter clutch, it may be possible to provide the technical result of reducing an inertia torque present at a transmission input shaft during gear shifting so that torque disturbances during transmission gear shifting may be reduced. Additionally, it may be possible to eliminate or reduce a mass of a dampening flywheel positioned between an engine and a driveline disconnect clutch, thereby improving vehicle fuel efficiency. For example, during transmission gear shifting, torque capacity of a torque converter clutch may be reduced such that the torque converter clutch slips and effectively reduces inertia present or observed at a transmission shaft located downstream of the torque converter clutch. Slipping the torque converter clutch may allow less inertia torque to be transferred from upstream of the torque converter clutch to a transmission input shaft located downstream of the torque converter clutch.
The present description may provide several advantages. Specifically, the approach may improve transmission gear shifting by smoothing transmission gear shifts. Further, the approach may improve vehicle fuel economy via reducing driveline inertia. In addition, the approach may reduce driveline cost by eliminating or reducing mass of a dampening flywheel. The described advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.